It is well known in motor vehicles that the aerodynamics characteristics of the vehicle body can be improved by an air dam mounted underneath the front of the motor vehicle and extending into proximity with the roadway. Such air dams may improve the handling and control of the motor vehicle and also improve the routing of air flow to the engine cooling system.
A disadvantage of the use of an air dam suspended underneath the front of the motor vehicle is that such air dams may be damaged by impact with obstructions such as driveway inclines and curbs. It has also been recognized that the aerodynamic performance of the air dam varies with the speed of the vehicle.
Accordingly, the prior art has recognized the advantage in having the air dam movably mounted beneath the front end structure of the vehicle body for movement between a nondeployed position in which the air dam is raised substantially above the road surface and a deployed position in which the air dam is lowered into proximity with the roadway. At low speeds the air dam remains in the nondeployed position and does not produce added drag when the air dam is not need to redirect the air flow for vehicle control or engine cooling.
In the prior art various hinges and linkages have been provided to enable movement of the air dam between the deployed and the nondeployed positions. In addition, the prior art has taught that the movement of the air dam may be provided by a mechanical or hydraulic actuator which is responsive to the vehicle speed to progressively deploy the air dam as the speed increases. In Chabot et. al. U.S. Pat. No. 4, 159,140 the air dam is mounted by hinges and links and is self deploying by the aerodynamic influence of air pressure acting on the air dam pivoting the air dam downwardly about its hinge and linkage arrangement.
It would be desirable to provide an improved air dam of the self deploying type in which movement between the deployed and the nondeployed positions would be obtained by the inherent flexure characteristic of the air dam structure without necessity for hinges and links and actuators.